The present invention relates to an ink jet recording method, a recording device and a data processing method in which high quality images can be formed on a recording material with suppressed banding nonuniformly, more particularly to the ink jet recording method, the recording device and the data processing method in which the recording is carried out through one-path or multi-path printing.
The present invention is applicable to any equipment using as the recording material, paper, textile, leather, nonwoven fabric, OHP sheet, metal or the like. More particularly, the present invention is applicable to a printer, copying machine, facsimile machine or another office equipment, industrial manufacturing machines or the like.
As regards the recording on the recording material using the recording apparatus, the demand for high-speed printing picks up. In order to increase the printing speed, it is one of the methods to refuse the number of paths in the multi-path printing which has been proposed to accomplish formations of high quality images. Here, the number of paths is the number of scans of the carriage required to complete one line of printing.
Since the number of ejection outlets of the recording head is limited, the amount of the sheet feed for units can be smaller if the number of paths is larger. On the other hand, the sheet feeding distance per unit can be increased by reducing the number of paths. For example, in the case that printing is carried out in the two-path mode, the speed can simply be doubled by changing it to one-path printing. That is, the reduction of the number of paths reduces the number of scans to cover a predetermined area (one sheet, for example), and increases the distance of sheet feed, so that time required for printing is shortened.
In the case that recording ahead having a plurality of ejection outlets for ejecting the recording liquid (ink) scans the recording material in the direction perpendicular to the direction in which ejection outlets are arranged, an image is formed in an image area in the form of a band by one scan of the recording head, as shown in FIG. 21.
Thus, in the case of the one-path printing, the duty (ratio) of the recording ink ejected per unit time is larger than when the one band area is printed through a plurality of scans (multi-path printing). Therefore, the production of the black stripe between the adjacent bands (paths) is remarkable at the portions where the printing duty is high, although it is different depending on the nature of the recording material and the recording liquid.
The problem is more significant in the case of lateral arrangement of the recording heads in which cyan, magenta and yellow recording heads or the like are arranged in the main scan direction. This is because the boundaries appear at the same position. FIG. 6 schematically shows the laterally arranged recording heads.
The black stripe appearing at the adjacent bands is called connecting stripe, spending or the like. It might deteriorate the image to such an extent that image is practically unsatisfactory.
Therefore, a method of avoiding the banding in one-path printing, thus improving the image quality, has been attempted.
For example, Japanese Laid-open Patent Application 11-188898 discloses a serial scanning type in which a recording head repeatedly scans the recording material in the main scan direction to print the image band by band, a method is used to avoid the production of a stripe at the connecting portion between the adjacent bands. More particularly, at least one of the first and the last raster lines of one band covered by one scan of the recording head is divided into a plurality of unit areas including a predetermined number of dots. In accordance with the image data, more particularly, with a sum of an amount of ink ejection for a noting color in each of the divided areas and an amount of ink ejections for the other in the unit areas, the amount of the ink actually ejected is reduced (thinning).
However, in the conventional method, the accuracy of the suppression of the banding in the case of plain paper or the like, with which the banding tends to occur, is poor.
Accordingly, it is a principal object of the present invention to provide an ink jet recording apparatus, a recording method and a data processing method with which the banding is suppressed even in the case of one-path printing.
According to an aspect of the present invention, there is provided an ink jet recording apparatus for effecting recording on a recording material by ejecting a plurality of inks with relative scanning movement between a recording head and the recording material, said ink jet recording apparatus, comprising obtaining means for obtaining relative information indicative of a relative relation between the amounts of inks to be ejected for each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material; determining means for determining, for each of the inks, a reduction rate at which the amount of the ink to be ejected to the neighborhood of the boundary in the unit area on the basis of the relative information for each of the unit areas obtained by said obtaining means and on the basis of quantity information indicative of an amount of each ink to be ejected in the unit area; and reducing means for reducing the amount of each ink to be ejected to the neighborhood of the boundary on the basis of the reduction rate for each ink determined by said determining means.
According to another aspect of the present invention, there is provided an ink jet recording apparatus for effecting recording on a recording material by ejecting a plurality of inks with relative scanning movement between a recording head and the recording material, said ink jet recording apparatus, comprising obtaining means for obtaining relative information indicative of a relative relation between the numbers of data corresponding to the inks to be ejected for each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material; determining means for determining, for each of the inks, a reduction rate at which the amount of the ink to be ejected to the neighborhood of the boundary in the unit area on the basis of the relative information for each of the unit areas obtained by said obtaining means and on the basis of the numbers of the data corresponding to each ink to be ejected in the unit area; and reducing means for reducing the data corresponding to each ink to be ejected to the neighborhood of the boundary on the basis of the reduction rate for each ink determined by said determining means.
According to a further aspect of the present invention, there is provided an ink jet recording apparatus for effecting recording on a recording material by ejecting a plurality of inks with relative scanning movement between a recording head and the recording material, said ink jet recording apparatus, comprising obtaining means for obtaining relative information indicative of a relative relation between the amounts of inks to be ejected for each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material; and reducing means for reducing an amount of each of the inks to be ejected to a neighborhood of a boundary in the unit area on the basis of the relative information for each of the unit area obtained by said obtaining means.
With the structure, the discrimination is made on the basis of the number of recording data (the number of dots to be printed) adjacent the boundary area as to the color area (hue and chromaticity) of a unit area (noting region), and the thinning rank is determined for each of the used inks and for each of the printing positions in accordance with the discriminated color area. By the thinning process for each of the inks using the thinning rank, the boundary stripe produced between the bands in a single path printing, can be suppressed.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.